1. Field of the Invention
This invention relates to a surface reforming method for such metal products as a mold for press molding a glass product, a mold for forging or press molding a metal product, and a mold for injection molding a plastic product.
2. Description of Prior Art and Problem to be Solved by the Invention
A mold for press molding glass products such as a glass optical disc substrate to be used as optical disc memory for a computer, video, audio, and the like, a glass hard disc substrate to be used for a computer, a glass lens to be used as an optical component, the front glass of a cathode-ray tube for a TV set, computer display, and the like, or a glass substrate disc and the like for a liquid crystal display has been known to be one in which that a platinum film is formed on a molding face of a mold comprising stainless steel, a refractory metal, and the like, with the aim of improving both the mold release and oxidation resistance. Also, as to a mold for forging or press molding a metal product and a mold for injection molding a plastic product, it has also been known that a platinum film is formed on the molding face with the aim of improving its exfoliation resistance and oxidation resistance.
However, a conventional mold for press molding a glass product has such a shortfall in the case of continuous press molding that exfoliation of the platinum film and abrasion of the molding face occur, causing the mold to have a relatively life of 10,000-20,000 shots. Therefore, the entire mold has to be replaced in a relatively short time, resulting in a high cost.
The purpose of this invention is to provide a surface reforming method for a metal product by solving the above problems and to improve both the exfoliation resistance of the platinum film formed on the surface of the metal product and the abrasion resistance of the surface.